/sci/ - Science & Math

>f '(x)

>dy\dx(x)

>ddxf(x)

>det(A)

>1+1

>grad(v)

>dx

>>8943714
>log(e) = 1

>x

>+ C

> [math]f_x[/math]

>dx/dy^2

>>8943714
>taking Automatic Control Systems
>professor writes arg(x) for arctan(x)
>uses something that looks like this for greek letter Zeta:
(
}

>>8943714
>log(x) used interchangeably with ln(x)

>let x be real

>the proof is left as an exercise

>y=

>y = kx + m

[math] c = \lambda f [/math]

>>8943920
i feel a deep anger within me when professors do this shit

>[math] F = m a[/math]

>>8943948
I had that happen on a midterm last quarter
Nearly lost my marbles then and there

>>8943914
Did they forget the d^2 before x or is the whole thing to the power of 2
Who does this?

>E = (hc)/(λ)

>300k starting

>tan tg
>sinh sh
>cosh ch
>csc cosec
>cot ctn cotan ctg

>[math]Succ(n)[/math]

>sinh(x)

>>8943714
>int(A)
>cl(B)

>let ... be infinitesimal

>cos(x)

>2 genders

>8.999...

>if( condition ) {
> code
>}

>>8943955
What the hell? Did the professor even notify you beforehand or even some type of warning?

>Cos(kπ) where k = 1, 2, 3, 4...

>+

> (x+2)/x = 2

FUCKING DUMBASS KIDS THAT DONT KNOW ALGEBRA

>>8944053
i don't get it

>>8944056
He's insulting people that think the expression he wrote is true.

>>8944056
Lots of kids cancel the x's disregarding the rules of fractions

>>8943955
Do you go to York?

> x = 2; 4; 6; ...
>not x ∈ {2; 4; 6; ...}

>f''''(x)

>f(((x)))

>>8944023
underrated post

>>8944018
>>8944403
>>>/pol/

>O(n log n)

>anything but log x for the natural logarithm

>Log(x)
>>8944729
is this even used IRL

>>8944780
in school we learned that it is common agreemen that log(x) is the log of base 10, and ln(x) is the log base e. ld is log of base 2.and log with a subscript is log of any base.

>>8944018
>>8944403
here we are all having a wholesome fun /sci/ time and you have to forget which board you're on.

>reals

>gcd(x,y)

>lg x

>>8944008
if anyone does this they should be ejected form whatever non-arts course they are doing

>ggT(x,y)

>>8943902
Wtf bruh its ln(e) not log(e)
stupid animeposter

>>8944787
>ld is a log of base 2
Never heard this one.

>>8945069
> tan^(-1) being used interchangebly with arctan

This one always bugs me.

>>8943758
this one triggers me

sin^-1(x) = arcsin(x) = 1/sin(x)

>>8945069
>taking multivariate calculus
>professor says "Some people use [math]tan^{-1}(x)[/math] instead of [math]arctan(x)[/math]. I'm afraid those people are wrong."
Loved that guy.

>>8945135
what a ledge

>>8944780
>>8944787
I learned it as
Log is log_10
ld is log_2
ln or Ln is log_e

log is foreign. It could be anything

>>8943714
> [math] \arcsin x + \arccos x = \frac{\pi}{2} [/math]

LOL

>>8945254
It actually is though

>>8943714
>small angle approximation

>>8945418
>when you're unsure if the answer is 0 or 8

in physics log(x) is base e unless another base is provided
considering that we aren't doing crazy mental arithmetic in our heads (which would make use of different base logs) and that every log can be written as a base e log, there's really no reason to ever use any other base. at least in physics.

>>8945442
>log instead of ln
>not saving time by writing one less letter while avoiding any ambiguities at the same time
brainlets they never learn

>>8944064
it's true for x=2

>>8945442
>there's really no reason to ever use any other base.

Tell that to a PH value.

>>8945093
Kek

>ds2=dx2+dy2+dz2-c2dt2

>>8945483

>Or to any field where you uses enormous number and have to plot them in a log scale to see something

>Physics :study of the sound
Fourier's study of a signal
Decrease of the eletrical signal through a filter...

>>8945135
The thing is 1/tan has a name, cotan. So tan^{-1} for the inverse function of tan seems pretty reasonable.

>>8944056


the real answer is 3

>>8943730
what's wrong with that notation

>>8946409

x is 3 for (x/+2)/x=2

but for (x+2)/x
if you expand its 1+(2/x)

>>8944065
Why is it not legit to cancel x here?

(x+2)/x=2=1+2/x=>x=2

>>8945077
I hope this is bait

>>8946412
I don't think this thread is about wrong notation.

>[math]\xi[/math]

>>8946701

Why do you think that?

>x/0

>>8946819
yeah seriously FUCK this

>[math]F=\frac{d\overrightarrow{p}}{dt}[/math]

>[math]\ni[/math]
>[math]\supset[/math]

>>8943714
>equal and opposite reaction

>>8943714
Good notation. Accurately conveys how exponentiation is just a function.
>>8944008
If you actually encounter this, problem's on you for reading a pop sci book instead of something rigorous. Unless the book is about non-standard analysis.

>2(10/5)

This confuses the american child.

$0.9999...=1$

[math] 1=2 [/math]

>>8945082
Weird, I don't care for detA; it just seems lazy to me.

>>8944729
My calculator has ln, and everyone I know says ln. I don't know why I would change it because some autist says something different.

>>8946473
No anon, the point is that they're saying it's true for all values of x. As in, the two x's completely cancel each other out, leaving you with just two.

>>8943714
Dislike this but I need to use it when handwriting complicated expressions, it just doesn't look clear otherwise :/

>>8943714
>a+b
>not sum(a,b)
>a*b
>not prod(a,b)
>a^b
>not exp(a,b)
Shit notation desu.

>(define (f x) ...)

>>8944020
Oh fuck that one in particular. So ugly

>[math]\times -5\; 6\; 7[/math]

>>8945135
>using [math]\tan(x)[/math] instead of [math]\arctan^{-1}(x)[/math]

>>8944403
Lol
>>8944537
>>8944789
It was a very, very slightly off-color joke.

>natlog(x)

>>8945551
The inverse function of tan also has a name, arctan. That's the issue.

>The plot of 1/[X] vs time is linear

>>8946872
it's about notation that annoys you
t. OP

>>8944023
Too underrated!

>>8944395
YES

>>8944780
Do you mean Log(x) instead of log(x)? If yes, then yes, it means the principal branch of log(x). If you mean log(x) vs ln(x), it sort of looks better. Has three letters like exp, sin, cos, tan etc. and doesn't use the awkward combination of ell and enn

>>8945454
Have you done any renormalization group?

>(x+y)^2=x^2+y^2

>>8947947
Oops, sorry >>8945442, wanted to quote >>8945454

>>8944020
what's wrong with that?

>>8947949
Fucked it up again. Guess I'm tired. Commute them up

>>8944787
Why would you even need to use logarithm of base different than e?

>>8946967
Your handwriting is atrocious regardless.

>>8947955
Base 10 if you're a shitty astronomer or something, calculating stuff via Pogson's empirical bullshit; base 2 if you're working with random paths and entropy and information theory and need to absolutely count the states.

>>8945047
Interesting space program you have here.

I tutor high school students and undergrads in physics and math. This thread was made for me.

>single step of algebra
>punch it into the calculator
>another single step of algebra
>punch it into the calculator
>repeat
Just do all the algebra symbolically and then go to the calculator at the end. More often than not you will cancel some stuff and save yourself a bunch of redundant calculations. You'll also make fewer computational mistakes the less you use your calculator. It's much easier to spot an error in algebra than to tell if some random ass number looks right.

I'm so glad my high school physics teacher made all quantities variables, whose values he didn't give until the end. Made me a better person.

>>8948226
I share your pain of tutoring high school students. I'll give you my favorites:

>(1/2) + (3/4) = 4/6
>2(xy) = 2x2y
>"what's 3-7?" "10?"
>f(x+h) = fh+fx
>precalculus student's that don't know what a quadratic is
>precaculus students that don't know how to write the equation of a line
>calculus students that don't know algebra

>diffy Q

Spherical coordinate conventions.
Physicist: [math]\phi[/math] is the azimuth, [math]\theta[/math] is the polar angle.
Mathematician: [math]\theta[/math] is the azimuth, [math]\phi[/math] is the polar angle.

While the physics convention is weird to me because [math]\theta[/math] is the angle in the [math]xy[/math] plane in polar coordinates, this particular math convention is more egregious because it isn't right-handed.

From what I've read, the physics convention is superior because foundational and important literature on the spherical harmonics uses it.

>>8943714
log base e(x)

>>8947337
Underrated

>assume

LOAD(LATEX_IN_BROWSER.exe)
GREENTEXT{MATHPRINT(\tan^{-1}(x))}
TEXTOUTPUT{"instead of"}
GREENTEXT{MATHPRINT(\arctan(x))}

>>8948595
that pic is cancer

>>8943902
python says this is correct

i'm tired of elitist retards

>[math]f^{-1}[/math] representing anything other than [math]\frac{1}{f}[/math]

>>8945551
The thing is inverse tan has a name, arctan. So tan^{-1} for the reciprocal function of tan seems pretty reasonable.

>succ(x)

>>8943758
FUCK
Almost forgot people do this.

>>8944022
>>8944284
I'm in Davis
We weren't warned before hand. I had to ask mid exam

>>8944395
>dots

>>8949552
what's wrong with it? it's the only notation I've ever seen used

>>8944537
>>8944789
pussies

>>8945135
[math] tan^{-1}(x) [/math] is standard functional algebraic notation and people who have unironic objections should go back to undergrad and stay there until they pass a first-year algebra and first-year mathematical logic course

>>8945022
>numbers exist

>>8943936
>>8943840
>>8943745
>>8947365
What the fuck

>>8945135
theres literally nothing wrong with [math]\tan^{-1}[/math] though.
the notation [math]g^{-1}[/math] denotes the inverse element of g wrt some operation.
for variables its [math]\cdot[/math] and for functions its [math]\circ[/math] unless stated otherwise.

>>8949620
There is no reason to use this notation except for the cases where you need absolute value of determinant. It just clutters things.

>>8950109
>using a potentially ambiguous notation when a function has a named inverse

>>8947955
Used in EE for signals and shit

>>8943714
>using superscript/subscript functions
>muh hyperoperations
the classic function notation is always teh best

>no units
>no legend
>nothing
I swear if I catch the faggot who wrote this in Gare du Nord, Paris, I'll hang them to a lamp post after a good old lynching.

People who's handwriting doesn't differentiate their [math] p [/math] and [math] \rho [/math]

[math]p = \rho_0gz[/math]

>>8948396
>(1/2) + (3/4) = 4/6

>>8951895
>people whomst'd've write "who's" instead of "whose"

>>8951914
fugggg

>[math] x\in\mathbf{R} [/math]

>>8943714
>cos^2(x)
>cos(x)cos(x)
>not cos(cos(x))

>>8951730
fag

>>8943714
\sqrt{-1} = i

>>8951990
>cos^-1(x) not sec(x)

>>8951990
wow i really hate you

>>8943714
There is 2 kinds of people:

>Kind 1
[math]\log x = \log_{10} x [/math]

>Kind 2
[math]\log x = \ln x [/math]

>>8951990
[math]f\circ g(x)[/math] is better than [math]f(g(x))[/math]

>>8952041
There a 2 kinds of people:

>wrong

>right

>>8951990
Fuck the haters, I agree with you.
[math]f^n(x)[/math] should represent iterated application for all functions and contexts and [math]f(x)^n[/math] should represent exponentiation, e.g. [math]cos(x)^2[/math]

>>8943970
/thread

>>8952041
there are two kinds of people:

>kind 1
[math]\log x = y[/math]

>kind 2
[math]\log_\alpha x = y, \qquad \text{where }\alpha \text{ is specified}[/math]

can you help me out? i quit studying over a decade ago and now i'm trying to catch up,
what the heck is that L supposed to mean?

>>8952074
Tell your mother to abort you before it's too late.

>>8947337
mah nigga

>>8944023
kek

>>8952526
A constant.

>>8952052
>writing the "o" when talking about Values of a function

>>8944023
Kek. That's my Nigga!

>>8944395
> >not [math] x \in \left\{ n \in \mathbb{N}\; |\; \frac{n}{2}\in\mathbb{N} \right\} [/math]